GB1258071A - - Google Patents

Abstract

Abstract 1,258,071. Anaesthetic systems. R. HESSE. 4 March, 1969 [4 March, 1968], No. 10419/68. Heading A5T. [Also in Division F2] A rebreathing anaesthetic system includes a valve arrangement having a gas release or blow off valve 8 which opens when a first (low) pressure in its vicinity in the system is exceeded and is closed by an arrangement including a pressure detector 9 when the pressure in the vicinity of the detector exceeds a second and higher pressure. The arrangement is to permit gases to be vented from the system during normal breathing, and if forced ventilation of the patient is necessary, extra pressure can be applied to the system and the gas release valve will be closed temporarily. Preferably the valve arrangement includes a housing 15 with inlet, outlet and bladder connections 16, 17, 18 and the pressure detector 9 closes the blow off valve element by means of a double armed lever 13. A one way valve 28 between the bladder connection and pressure detector and the blow off valve compels the pressure pulse originating in the squeezed bladder to pass to the patient before reaching the blow off valve. The pressure at which the detector 9 causes the blow off valve to close may be varied, e.g. by means of a movable magnet 21 and an iron armature 22 carried by the lever. In alternative arrangements the bellows 9 is replaced by a piston (10 Fig. 3 not shown) in a cylinder (11); the higher pressure at which the blow off valve is closed may be altered by means of a sliding weight (31 Fig. 4 not shown); the lever may be replaced by telescopic (34 Fig. 5 not shown) or flexible (33 Fig. 6 not shown) connectors linking the detector and blow off valve element 14; by means of a curved conduit (36 Fig. 7 not shown) from valve housing 15, bellows 9 itself may act on the valve element 14, to close it at the higher pressure. In an emergency, button 37 may be pressed to hold the blow off valve open to release gas.

Inventors

No inventors recorded.

Bibliographic Details